The people who bought the cotton from the slave-owning Confederate States were called 'mill-owners'. Don't get me going about mill-owners...

You can also include the owners and operators of the blockade runners, which included many new fast ships specially built for that service, anticipating huge profits.

The lack of imported cotton caused great hardship in Lancashire, called the Lancashire Cotton Famine. Of course the people who suffered were the poor labouring classes, who ended up in the poorhouse.